Venture Global LNG Inc. said a subsidiary of Royal Dutch Shell plc has agreed to purchase additional supplies of liquefied natural gas (LNG) from the $4.5 billion Calcasieu Pass export facility under development in Cameron Parish, LA.

On Tuesday, Venture said its subsidiary, Venture Global Calcasieu Pass LNG, and Shell NA LNG LLC have agreed to modify their existing 20-year sales and purchase agreement (SPA). Under the revised SPA, Shell will now purchase two million tonnes per annum (mtpa) of LNG from Calcasieu Pass, which is expected to come online in 2021.

The original SPA was signed in February 2016, when Shell had agreed to purchase 1.0 mtpa of LNG from Venture through Calcasieu Pass.

The revised agreement with Shell follows a separate 20-year SPA with Italy’s Edison SpA, signed last September, for 1.0 mtpa through Calcasieu Pass. Combined, the agreements bring the facility’s total committed capacity under binding 20-year contracts to 3.0 mtpa.

“Shell’s additional purchase is a huge milestone, we believe a breakout event, and a significant validation of our best in class approach on our path to commencement of construction later this year,” said Mike Sabel and Bob Pender, co-CEOs at Venture.

In 2015, Venture’s Calcasieu Pass subsidiary and TransCameron Pipeline LLC applied at FERC for authorization to construct the LNG terminal and associated natural gas pipeline laterals [CP15-550]. That same year, the Department of Energy (DOE) authorized Venture to export up to 620 Bcf/year of LNG from Calcasieu Pass to free trade agreement (FTA) countries.

Last September, Venture said it expected the Federal Energy Regulatory Commission to give its final approval for Calcasieu Pass in early 2018, as well as DOE authorization for non-FTA exports. At the time, the company said it planned to make a final investment decision (FID) by 2Q2018. Assuming the FID is agreed upon, construction at Calcasieu Pass would begin in mid-2018, with operations scheduled to begin in early 2021.

Plans call for the Calcasieu Pass terminal to be built on a 1,000-acre site near where the Calcasieu Ship Channel meets the Gulf of Mexico. It would include two ship-loading berths for LNG vessels, two full-containment LNG storage tanks and an on-site combined-cycle gas turbine power plant.

Calcasieu Pass would have a nameplate capacity of 10.0 mtpa of LNG. TransCameron’s pipeline system would consist of two laterals totaling 43 miles and would be constructed with 42-inch diameter pipe.

Venture is also looking to develop a second LNG export terminal, with 20.0 mtpa nameplate capacity of LNG, in Plaquemines Parish, LA. The $8.5 billion Plaquemines facility would be built on a 632-acre site at river mile marker 55 on the Mississippi River, about 30 miles south of New Orleans.

Two Venture subsidiaries, Venture Global Plaquemines LNG LLC and Venture Global Gator Express LLC, filed an application with FERC for the Plaquemines facility in February 2016.

The Plaquemines facility is expected to include up to three marine loading berths capable of receiving oceangoing LNG carriers up to 185,000 cubic meters in capacity. It would also include a utility dock on the Mississippi River to handle waterborne deliveries of equipment and material during both construction and project operations. A combined-cycle gas turbine power plant with generating capacity of 720 MW also is to be developed; another similar plant is to be added in a second phase.

Last week, an LNG tanker owned by Shell departed Dominion Energy’s new LNG export terminal at on Chesapeake Bay in Maryland with the facility’s first export cargo. FERC gave authorization for Dominion to begin commercial exports from Cove Point on Monday.

Cove Point is the second U.S. facility to export LNG sourced from domestically produced natural gas in the Lower 48. Cheniere Energy Inc.’s Sabine Pass LNG terminal in Cameron Parish, LA, began exporting gas in February 2016.

Cheniere and India’s state-owned natural gas utility, Gail (India) Ltd., officially kicked off their 20-year SPA on Monday. An agreement between Cheniere and Gail Global (USA) LNG LLC, a U.S. affiliate, was first agreed to in December 2011.

Shell issued a report last week that found LNG demand was strong in 2017, and it predicted LNG demand would increase at an average rate of 4%/year over the next 20 years. Shell also reported that 1,100 spot cargoes were delivered in 2017, a 17% increase from 2016 and equivalent to three cargoes delivered every day.